Computer systems are widely known. In particular, a number of modern computer systems have a power supply for supplying a mainboard having a processor and a BIOS component, as well as a network component connected thereto. If the network component is supplied with an operating voltage, even in a so called standby state by the computer's power supply, it is possible to wake up the computer by means of suitable requests via a communications network, i.e., to put it into the operating state. For instance, the so called ATX (Advanced Technology Extended) standard permits the supplying of a network card in a standby state for recognizing so called magic packets according to the “Wake on LAN” (WoL) standard.
Such computers have the advantage, among others, that they can be maintained remotely. For example, a system administrator of a company network can wake up computer systems connected to the company network and install new software components remotely on the computer systems. Methods and interfaces for remote maintenance are known, in particular, as Intel Active Management Technology (AMT) or Alert Standard Format (ASF). Other functions are made available by the so called standby operation as well. In this regard, the ACPI (Advanced Configuration and Power Interface) in particular, provides a plurality of operating states in which a processor of the computer system is indeed stopped or turned off, but other components of the computer system are still supplied with an operating energy.
The drawback with such systems generally is their relatively high power consumption in the standby state. For instance, most computers in a company network are not used at night and on weekends. While they are in a standby state, however, they still consume a certain amount of power, 5 W, for example, in order to continue supplying components that are still active, such as network cards, with an operating energy. Furthermore, the efficiency of the switching power supplies typically used in computer power supply units declines with low capacity utilization, so that the energy balance in the standby state becomes even worse.